Locks are well known and used by every household. Generally speaking, there are two types of locks commonly used as door locks, passage lock and deadbolt lock. The passage lock typically includes a bolt mounted on a door frame along with a door knob and other connecting mechanism. The bolt usually has a surface slanted in relation to a longitudinal direction to which the bolt moves. The bolt that can slide, along the longitudinal direction, in and out of a receiving hole on a door frame with turn of the door knob. The bolt can be fixed on its extended position when a button on the door knob is pressed, thus locking the door. The deadbolt lock, on the other hand, typically includes a bolt that has a longer body and a surface that is perpendicular in relation to the longitudinal direction. The bolt can slide in and out of a receiving hole on the door frame with movement of a key inserted into the deadbolt lock. When a user wants an added security to his house, he usually installs a deadbolt lock in addition to the passage lock.
Electronic door locks are also well known and commonly used in the hotel industry. An electronic door lock generally includes an electronic control mechanism and a locking mechanism. The locking mechanism generally includes a deadbolt lock and a passage lock, each separated from the other. The electronic control mechanism typically unlocks the deadbolt and engages the passage lock. From inside, the deadbolt lock is usually activated by a turn knob placed above the door handle, putting the lock in passage mode. These electronic door locks are widely used by hotels, but they are not easily retrofitted into older doors where there is only one opening on the door frame for the passage lock. For hotel operators and residential home owners who like to have security of a deadbolt lock, they have to go through the job of modifying both the door and the door frame before a deadbolt lock can be installed.